Published online by Cambridge University Press: 15 May 2009
(1) The young of parents both of which have been injected with an immunising mixture of diphtheria toxin and antitoxin, show immunity of the same order as that of young from similarly treated mothers and normal fathers.
(2) The injection of certain foreign substances into a female guinea-pig appears to have a direct effect on the offspring in diminishing their resistance to diphtheria toxin, shown equally well by the young of mothers injected, (a) before the attainment of sexual maturity, (b) during pregnancy, and (c) after birth during the period of lactation.
(3) A single injection of diphtheria toxin may give rise to a condition of active immunity (as tested by the resistance of the young) in guinea-pigs possessing hereditarily transmitted passive immunity. Should this injection of toxin give rise to great constitutional disturbance, the young may show lowered resistance, whereas, if it give rise to but slight constitutional disturbance, the young show a high degree of immunity. These effects appear to be accentuated if similar injections are repeated in the next generation.
1 The supply of test toxin 98A, with which all the earlier tests were carried out, ran short in August 1909, and toxin 98B, and in a few instances 967 A, was then used. In all results given so far no toxin number has been recorded because 98 A was used throughout, in all subsequent tables the toxin number is given. The relative values of the toxins used are as follows:
Original M.F.D. 98 A and B under 0.003 c.c. {Average M.F.D. when used 98 A, 0.008 c.c. Original M.F.D. 967 A 0.002 c.c. Average M.F.D. when used 98 B, 0.014 c.c. Average M.F.D. when used 967 A, 0.004 c.c. 98 A and B were two bottles filled at the same time with the same toxin prepared in 1900, 967 A was prepared in March 1909. The L0 doses were similar, that of 98 A 0.27 c.c. and that of 967 A 0.32 c.c.